1. Field of the Invention
The present invention is related to a non-detachable structure of a lamp bulb and its lamp holder, and especially to such a structure of a lamp bulb and its lamp holder capable of preventing a user to detach by himself for changing when the lamp bulb is damaged.
2. Description of the Prior Art
Conventional decorative lamps such as Christmas lamp strings mostly have linear specific lengths; they can illuminate or flash through the function of lightening of the lamp bulbs thereon. Such conventional lamp strings can only give quite limited variation, for example, they can only be pulled to form a letter xe2x80x9cVxe2x80x9d or wrapped around a Christmas tree. Therefore, people design some imitative shapes of articles (such as stars, Christmas trees etc.) as frames, then lamp beads are mounted on the frames one by one, thereby, the are provided with the decorative shining function as stars or Christmas trees are. However, their effects of lamp variation are still limited, and the volumes of the imitative frames are overly large, packaging and transportation of them are inconvenient.
In the recent years, decorative lamps in the form of net lights or knitting lights are produced to breakthrough the aforesaid limitation, In such a net light or knitting light; the largest function thereof is that it can be individually hung for decoration, or it can be stuck to a flexible base plate, on the base plate, there is a desired pattern depicted, The lamp string can be combined with the flexible base plate, the pattern of the entire decorative lamp string can thus be more variant, the lamp string can be wrapped to reduce its occupying volume. And the net light or the knitting light is convenient for direct wrapping around a decorative article (such as a Christmas tree). Such net light or knitting light has the aforesaid advantages, nonetheless, variation of lamp flashing of the entire light still can only be decided by different flashing rate or different colors of the lamp beads, its function of illuminating and decorative flashing is still inadequate.
Accordingly, U.S. Pat. No. 5,951,146 provided a net light including therein a braided pattern, of which the entire net plane is formed by intercrossing braiding a plurality of lamp strings individually with a loop. The lamp strings each can form any of various randomly designed patterns and letters by selective arrangement of the lamp beads and a lamp string, and the lamp strings can be controlled by separately turned on/off by means of the separated switches for the lamp strings having a monocrystalline integrated electric circuit provided with a control program; so that driving of the program of the integrated electric circuit forms a single sequential or intermittent output, and that the a plurality of lamp strings can generate more variant flashing correspondingly, and the entire knitting decorative lamp can provide the decorative function of having more flashing patterns or letters.
Such decorative net light formed by the lamp strings individually with a loop has each of the loops comprised of different number of lamps bulbs. For example, if one of the loops forms a larger lamp string pattern, its number of lamp bulbs will be larger; on the contrary, smaller pattern needs fewer lamp bulbs. Assuming that each lamp string is supplied by a power source of same voltage, the voltage of each lamp bulb serially connected in every individual loop is different, for example, if a lamp string with 10 lamp bulbs is supplied with a voltage of 220 V, then the voltage of each lamp is 22 V. While for a lamp string with 20 lamp bulbs, the voltage of each lamp is 11 V.
From the difference stated above, when a lamp bulb of the above stated lamp strings with a plurality of separated loops is damaged, a lamp bulb with the same value of resistance with that of every other lamp bulb in the corresponding lamp string with its individual loop is substituted for it. A decorative net plane may have lamp bulbs of multiple different values of resistance, a common user is uneasy to distinguish for detaching them. But lamp bulbs and their lamp holders now available are all detachable, a user detaches by himself may induce worrying of safety in using the lamp bulb products.
The object of the present invention is to provide a non-detachable structure of a lamp bulb and its lamp holder, wherein, an engaging mechanism is provided at the joint of a bottom connecting member of the lamp bulb with the lamp holder, when the two are connected at the joint, the lamp bulb can be prevented from direct detaching from the lamp holder by providing the engaging mechanism.
In one of the feasible embodiments, the above stated engaging mechanism includes an inner peripheral annular rib which allows a corresponding annular flange provided on the bottom connecting member of the lamp bulb to be forcedly pressed into engagement therewith.
In another one of the feasible embodiments, the inner peripheral annular rib is substituted by a plurality of intermittently arranged protruding points.
And in another one of the feasible embodiments, the inner peripheral annular rib is substituted by a bevel inner groove, and the corresponding annular flange provided on the bottom connecting member of the lamp bulb is beveled in corresponding to the bevel inner groove in obliquity for engagement with the inner groove.
In a further one of the feasible embodiments, the engaging mechanism including is provided on the top of the opening of the lamp holder with an outer peripheral annular flange, while the bottom connecting member of the lamp bulb is provided with a corresponding engaging flange for engaging with and locking the annular flange.